The latest observations of Jakobshavn Glacier show that Greenland’s largest glacier is moving ice from land into the ocean at a speed that appears to be the fastest ever recorded. Researchers from the University of Washington and the German Space Agency measured the speed of the glacier in 2012 and 2013. The results were published Feb. 3 in The Cryosphere, an open-access journal of the European Geosciences Union.

The new observations show that in summer of 2012 the glacier reached a record speed of more than 10.5 miles (17 kilometers) per year, or more than 150 feet (46 meters) per day. These appear to be the fastest flow rates recorded for any glacier or ice stream in Greenland or Antarctica, researchers said.

The scientists note that the summer speeds are temporary, with the glacier flowing more slowly over the winter months. But they point out that even the glacier’s average annual speed over the past couple of years is nearly three times its average annual speed in the 1990s.

This speedup of Jakobshavn means that the glacier is adding more and more ice to the ocean, contributing to sea-level rise.